Structural glass unit

ABSTRACT

A structural glass unit comprises a multi-ply glass assembly, for example a glass laminate or a sealed double glazing unit, which may be part of a roof structure. The glass assembly has a stepped configuration at a location where the assembly is secured to a supporting member by a clamp which is clamped to one glass sheet only of the glass assembly.

This application is a continuation of application Ser. No. 888,469,filed July 23, 1986 now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to structural glass units and in particular tostructural glass units comprising a multi-ply glass assembly, such as aglass laminate or double glazing unit, which is used in a situation, forexample as part of a roof structure, where it is desirable to secure thestructural glass unit against a bending moment.

It is known to secure a glass laminate to a supporting structure bymeans of bolts which extend through aligned holes in the glass sheets ofthe laminate and the plastics interlayer material. GB 1 272 774describes such a laminated structure for use as an aircraft window.There is also in U.S. Pat. No. 4,204,374 a description of an aircraftwindshield which is bolted to the airframe structure.

GB 2,148,372 A describes a glass assembly comprising a planar array ofsealed multiple glazing units which are secured to supporting members bymechanical fixings which pass through the outer sheets of the unitsoutside the seals of those units. The outer sheets are sealededge-to-edge.

When using laminated glass units in architectural structures it has beenfound that if the edge of a laminate is gripped sufficiently tightly tosupport the edge of the laminate against a bending moment, the pressureon the interlayer of plastics material causes the interlayer to exudefrom the laminate. It has also been found that if the edge of a sealedmultiple glazing unit is gripped too tightly the pressure may causedeformation of the spacer strip, usually an aluminium spacer and of thesealant which is used to seal the spacer strip between the panes of theglazing unit.

This invention is based on the discovery that this problem can beovercome and a more secure load bearing connection can be achieved bysecuring the multi-ply glass assembly by connection to one glass sheetonly of the assembly.

SUMMARY OF THE INVENTION

According to the invention there is provided a structural glass unitcomprising a glass assembly having a stepped configuration at a locationwhere the glass assembly is secured to a supporting member by a clampwhich is clamped to one glass sheet only of the glass assembly.

Preferably the glass assembly has a stepped configuration along one edgeand is secured to the supporting member by clamps at least at twolocations along that edge.

The glass assembly may be inclined at an angle of at least 15° to thevertical and supported principally in the region of opposite horizontalmargins, the glass assembly having a stepped configuration at a locationon one of said margins where it is secured to a supporting member by aclamp which is clamped to one glass sheet only of the assembly so thatsaid margin is not free to flex and the glass assembly is subject to abending moment about that margin.

In one embodiment for architectural use the glass assembly is a glasslaminate. The glass laminate may comprise two glass sheets laminatedtogether by a plastics interlayer, one of the sheets being a toughenedglass sheet which is larger than the other sheet, thereby forming thestepped configuration.

Preferably both sheets of glass are toughened. Said one glass sheet maybe formed with at least one hole for attachment of a clamp.

In another embodiment, also for architectural use, the glass assemblymay be a sealed double glazing unit.

Preferably the inner pane of the double glazing unit is inset from theouter pane to form a stepped configuration, and a clamp for securing toa supporting member is clamped to the outer pane outside the seal of thedouble glazing unit.

The inner pane may be inset from the outer pane at least at twolocations along the lower margin of the double glazing unit, formingflanges at those locations with fixing holes in those flanges outsidethe seal of the double glazing unit for attachment of clamps forsecuring the double glazing unit to a supporting member.

The invention also comprehends a glass roof structure comprising anumber of the structural glass units of the invention, which units areinclined and are positioned edge-to-edge with the bottom of each unitsecured to a supporting member for the roof.

The bottom edge of the clamped glass sheet of each glass assembly mayoverlie a gutter of the roof.

Two series of structural glass units of the invention may co-operate toform a ridge roof, with the glass assemblies of each series positionededge-to-edge, the bottom of each glass assembly secured to a supportingmember for the roof, and the tops of facing glass assemblies connectedjust below the roof apex by knuckle joints whose components are securedto the facing glass assemblies.

In a preferred ridge roof structure the abutting edges of the glassassemblies of each series are spanned near their tops by the knucklejoints.

In a glass roof structure in which two series of structural glass unitsof the invention co-operate to form a ridge roof, with each structuralglass unit including a double glazing unit, the double glazing units ofeach series may be positioned edge-to-edge, the bottom of the inner paneof each double glazing unit secured to a supporting member for the roof,and the tops of the facing double glazing units connected just below theroof apex by knuckle joints whose components are secured to the facingdouble glazing units by fixing assemblies attached to the outer panes ofthe double glazing units without impairing the seals of those units.

Preferably in this roof structure of double glazing units each fixingassembly passes through a sealed hole in the inner pane of a doubleglazing unit, within the perimeter seal of the double glazing unit, witha clearance sufficient to facilitate the flexing of the double glazingunit under wind load, and that fixing assembly passes through a hole inthe outer pane of the unit and is clamped to that outer pane only.

Each fixing assembly may include a boss positioned between and sealed toboth panes of the double glazing unit.

In a preferred ridge roof structure with double glazing units, theabutting edges of the double glazing units of each series are spannednear their tops by the knuckle joints.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the invention will now be described, by way ofexample, with reference to the accompanying drawings in which:

FIG. 1 is a top plan view of part of a ridge roof structure according tothe invention made up of structural glass units of the invention,

FIG. 2 is a cross-section through a trough of the ridge roof structureof FIG. 1,

FIG. 3 is a cross-section through a ridge of the ridge roof structure ofFIG. 1,

FIG. 4 is an elevation in the direction of arrow IV in FIG. 2 showing aclamping assembly at the bottom of one laminate of the roof,

FIG. 5 is a view in the direction of arrow V of FIG. 3 showing a knucklejoint spanning the abutting edges of two laminates of the roof,

FIG. 6 is a view similar to part of FIG. 2 showing the clamping of thelower margin of a sealed double glazing unit in a ridge roof structure,

FIG. 7 is a cross-section similar to FIG. 3 through a ridge of a ridgeroof structure employing sealed double glazing units, and

FIG. 8 is a detailed view of a fixing assembly employed in the ridgeroof construction of FIG. 7.

DETAILED DESCRIPTION

Referring to the drawings a ridge roof structure comprises a number ofstructural glass units 1. These glass units are arranged as two seriesindicated generally at 2 and 3. The structural glass units of eachseries are inclined and cooperate to form the ridge roof. Eachstructural glass unit 1 comprises a multi-ply glass assembly, in thisembodiment a glass laminate 4, FIGS. 2 and 3, preferably consisting ofsheets of toughened glass.

In the illustrated embodiment, the glass laminate 4 consists of an outersheet of toughened glass 5 which is 12 mm thick and an inner sheet oftoughened glass 6 which is 6 mm thick. These glass sheets are bondedtogether by a plastics interlayer 7 for example of polyvinylbutyral. Thebottom of each laminate is secured to a supporting member 8 which is aglass fixing bracket, which is itself bolted to a roof member 9 which isbolted at 10 to a node point of a basic structural framework 11. Thereis a glass fixing bracket 8 bolted to each side of the roof member 9.

The outer glass sheet 5 of each unit is larger than the inner glasssheet 6 of that unit so that the laminate has a stepped configurationalong its lower edge where the structural glass unit is to be secured toglass fixing brackets 8. As shown in FIG. 2 two of the brackets 8 areclamped to the outer glass sheet 5 by means of clamps which are attachedto spaced holes 12 near the bottom edge of the outer sheet 5. The clampsclamp the bottom margin of the sheet 5 and restrain it from flexingunder the weight of the sheet.

The drilling of all necessary holes in the glass sheets 5 of thelaminate is carried out before the sheets are toughened and laminated.

FIGS. 2 and 4 show how the outer glass sheet only is clamped by clampseach of which is fixed to the upper end of a bracket 8 Each clampcomprises an outer clamp plate 13 which bears, through a gasket 14, onthe outer face of the outer glass sheet 5 and an inner clamp plate 15which bears on the outer face of the upper end of the bracket 8. Agasket 16 is located between the bracket 8 and the inner face of thesheet 5. A clamping bolt 17, preferably of high tensile steel, passesfrom the outside through the clamp plate 13. Steel washers 18 arelocated between the head of the bolt 17 and the clamp plate 13 andbetween the bracket 8 and the clamp plate 15, and the bolt passesthrough a bush 19 located in the hole 12 in the glass sheet 5. A nut 21is tightened on to the end of the bolt 17 to a predetermined torquewhich will depend on the design load of the roof and the dimensions ofthe units, and bears against the clamp plate 15, which extends upwardlyto lap the lower edge of the inner glass sheet 6. The lower edge of theinner sheet 6 is located on the upper edge of the bracket 8 usingsetting blocks 22.

Near the top corners of each laminate there are aligned holes 23 and 24in the outer and inner glass sheets 5 and 6. The holes 23 in the outersheets 5 are countersunk as illustrated in FIG. 3. FIG. 5 shows how theabutting edges of the inner sheets 6 of two adjacent laminates of eachseries are spanned near their tops by a knuckle joint comprising twojoint plates 25 and 26. A head 27 extending along the upper edge ofjoint plate 25 interlocks into a socket 28 extending along the upperedge of joint plate 26. Each of the joint plates is fixed to each of theabutting laminates and each fixing comprises a bolt 29 whose head fitsflush into a bush 30 in one of the countersunk holes 23, 24 in the outerglass sheet 5. Each bolt 29 passes through a steel clamping disc 31which bears on the inner face of the inner glass sheet 6 through agasket 32. The disc 31 is clamped against the glass sheet by a nut 33.The appropriate joint plate 25 or 26 is secured on the bolt 29, betweensteel washers 34, by a nut 35. The laminate at the right-hand side ofthe ridge as shown in FIG. 3 is slightly shortened so that the upperedge of the laminate at the left-hand side rises above it to form theactual apex of the roof. The space between the upper edges of the facinglaminates is filled with translucent silicone sealant 36. Similarsealant also fills the spaces between the edges of adjacent laminates ofeach series as indicated at 37.

FIG. 2 shows a gutter 38 which is supported by a spacer 39 on the roofmember 9. The bottom edge of the clamped sheet 5 of each inclinedlaminate overlies the gutter. The upper edges 40 of the gutter slopeoutwardly to accommodate the bottom edges of the sheets 5.

With this construction two secure load bearing connections are made tothe bottom margin of each structural glass unit, each connectionclamping the bottom margin so that it is not free to flex, andsupporting the unit against the bending moment, resulting from theweight of the unit, about that margin. The knuckle-joint interconnectionof facing pairs of abutting laminates below the apex of the roof ensuresthat the roof can flex as the wind loading changes, while the roof hassufficient stiffness over its whole span.

The ridge roof construction may be a single ridge, or a ridge roofconsisting of a number of parallel ridges and covering a large floorarea, for example a factory building.

FIG. 6 illustrates a modification of the ridge roof structure of FIG. 2,in which each glass assembly is a sealed double glazing unit comprisingan outer pane 41 of toughened glass which is 10 mm or 12 mm thick. Theinner pane, indicated generally at 42, is a glass laminate comprisingtwo sheets 43 and 44 of annealed or toughened glass. Each of the sheets43, 44 is 3 mm thick and the sheets are laminated together with aninterlayer 45 of polyvinylbutyral which is 0.4 mm thick. The two panes41 and 42 are spaced apart by an aluminium spacer 46 of conventionalcross-section and are secured to the spacer by a silicone sealant 47.The sealed interspace 48 between the panes 41 and 42 is, in thisembodiment, 16 mm wide.

The lower edge of the inner pane 42 is inset from the outer pane 41 toform a stepped configuration along the lower margin of the doubleglazing unit as illustrated in FIG. 6. Alternatively the steppedconfiguration instead of extending the full width of the unit may beprovided locally at each lower corner of the double glazing unit or atother spaced locations along the lower margin of the double glazingunit. The spacer 46 is shaped to conform to the outline of the innerpane and follows the shape of the lower edge of the inner pane. Aperipheral seal is thus maintained around the double glazing unit.

The outer pane 41 therefore provides a flange or flanges 49 extendingbeyond the inner pane. Before toughening two holes 12 are drilled in theflange or flanges 49 at spaced locations along the lower edge of theouter pane.

In the same way as illustrated in FIG. 2 the flange(s) 49 of the innerpane are secured to supporting brackets 8 by means of clamps so that thebottom margin of the double glazing unit is clamped to restrain it fromflexing under the weight of the double glazing unit.

First of all each double glazing unit is located on the brackets 8 usingsetting blocks 50 for seating the step of the double glazing unit ontothe supporting brackets 8. Each flange 49 is then clamped to its bracket8 using a clamp similar to that described with reference to FIG. 2, butincluding a metal spacer 51 between the gasket 16 and the inner clampplate 15. The lower margin of the double glazing unit is thus secured tothe roof structure at locations outside the seal of the double glazingunit.

In the same way as with the laminated glass assemblies of FIGS. 1 to 5,the double glazing units are positioned edge-to-edge and the tops of thefacing double glazing units at the ridge of the roof are connected justbelow the roof apex by knuckle joints whose components are secured tothe facing double glazing units as illustrated in FIG. 7. The knucklejoints 27, 28 are secured to the facing double glazing units by fixingassemblies attached to the outer panes 41 of the double glazing unitswithout impairing the seals of those units. In the same way asillustrated in FIGS. 3 and 5 the abutting edges of the double glazingunits of each series are spanned near their tops by the knuckle joints.Each double glazing unit is fixed to the knuckle joints at two locationswhich are spaced apart and along the upper edge of the double glazingunit, within the seal of the double glazing unit. Along the upper marginof each double glazing unit at the ridge of the roof the outer pane 41extends beyond the inner pane 42 to form an upper flange 52. In theembodiment illustrated in FIG. 7 the double glazing unit to theleft-hand of the drawing would have a slightly greater height dimensionthan the double glazing unit to the right of the ridge so that the upperedges of the outer panes 41 and the inner panes 42 can overlap at theroof ridge with appropriate spacing for the introduction of siliconesealant 53 between the upper edges of the flanges 52 at the top of theridge and between the upper edges of the inner panes 42 at the apex ofthe inside of the ridge. The space between the upper flanges 52 of theouter panes is filled with a packing foam 54.

Before the outer panes 41 of the double glazing units are toughened,holes are drilled in the panes for the clamping of the fixingassemblies. At each fixing position the outer pane 41 has been drilledwith a countersunk hole 55, FIG. 8, and the laminated inner pane 42 hasa hole 56 through which the fixing assembly passes with clearance. Eachfixing assembly includes a fixing member in the form of a long stainlesssteel bolt 57 which passes right through the double glazing unit and issecured to one of the joint plates 25 or 26 of the knuckle joint. Thehead 58 of the bolt fits into a shaped stainless steel cup washer 59which itself engages in a bush 60 which is made of a resilient material,for example Nylon (Trade Mark). The bush 60 has a tapered head which isa free fit in the countersunk hole 55 in the outer pane 41. The bush 60carries the bolt 57 through the hole 55 and is a loose fit on the bolt57. The outer surface of the bush 60 has a thread which engages with aninternal thread, as indicated at 61, in a central aperture 62 whichpasses through a metal boss 63, for example of aluminium, which ispositioned between and is sealed to both panes 41 and 42.

The boss 63 is of generally cylindrical form with an annular groove 64in its outer face in which a sealing O-ring 65 for example of Nylon(Trade Mark) or silicone rubber or neoprene rubber is seated. Theoutside diameter of the metal boss 63 is slightly larger than thediameter of the hole 56 in the inner pane 42. During assembly of thedouble glazing unit the boss 63 is located on the outer pane 41 beforethe inner pane 42 is placed on the spacing frame 46.

The inner portion 66 of the boss 63 is of reduced diameter and issituated, with clearance, in the hole 56 in the inner pane. The inwardpart of the central aperture 62 through the boss 63 is of hexagonalinternal shape and acts as a hexagonal socket for the insertion of a keywhich is used for tightening the boss 63 onto the thread of the bush 60.When assemblying these parts a flexible silicone sealing compound 67 isspread between the outer surface of the boss 63 and the inner surface ofthe outer pane 41, up to the sealing ring 65. The boss 63 is tightenedonto the bush 60 so as to clamp the fixing assembly to the outer pane41. The space between the boss 63 and the inner pane 42 is then filledwith sealing compound 68 so that the fixing assembly passes through thedouble glazing unit without impairing the seal of the double glazingunit. The clearance between the inner part 66 of the boss and the hole56 in the inner pane 42 is sufficient to facilitate the flexing of theunit under wind load for example. An aluminium spacer 69 is thenthreaded on to the bolt 57 and is tightened against the inner part 66 ofthe boss. A resilient gasket is then placed over the bolt and theprotruding end of the bolt is passed through a wide hole 71 in the jointplate 25. A further resilient gasket 72 is placed over the end of thebolt and a self-locking nut 73 of stainless steel is tightened on to theend of the bolt to secure the fixing assembly to the knuckle joint plate25. This mode of clamping each double glazing unit adjacent its uppermargin to the joint plates ensures that when the double glazing unitsare subject to wind load the seals of the double glazing units aremaintained due to the ability of the fixing assemblies to float in theholes 56 in the inner panes 42 without damaging the seal.

While some embodiments of this invention have been illustrated anddescribed, it is understood that various modifications and changes willbecome obvious to those skilled in the art. Such modifications andchanges may be made without departing from the true scope and spirit ofthis invention.

I claim:
 1. An architectural structural glass unit comprising a glassassembly including at least two parallel glass sheets assembledtogether, the glass assembly being inclined at an angle of at least 15°to the vertical and supported principally at opposite upper and lowerhorizontal margins and having a stepped configuration at locations onsaid lower margin where the glass assembly is secured to a supportingmember by clamps which are clamped to one glass sheet only of the glassassembly at separate locations along said lower margin so that saidlower margin is not free to flex and the glass assembly is subject to abending moment about said lower margin, said at least two glass sheetsbeing connected to one another independently of said supporting members.2. An architectural structural glass unit as claimed in claim 1, whereinsaid at least two glass sheets are laminated together.
 3. Anarchitectural structural glass unit comprising a sealed double glazingunit which includes an inner pane and an outer pane, the double glazingunit being inclined at an angle of at least 15° to the vertical andsupported principally at opposite upper and lower horizontal margins andhaving a stepped configuration at locations on said lower margin wherethe double glazing unit is secured to a supporting member by clampswhich are clamped to one pane only of the double glazing unit withoutimpairing the seal of that unit and so that said lower margin is notfree to flex and the double glazing unit is subject to a bending momentabout said lower margin, and the double glazing unit being furthersupported at locations at said upper margin of the double glazing unitby fixing assemblies which are secured to the outer pane only withoutimpairing the seal of the unit, said inner and outer panes beingconnected to one another independently of said supporting members.
 4. Anarchitectural structural glass unit as claimed in claim 3, wherein theinner pane is inset from the outer pane at least at two locations alongthe lower margin of the double glazing unit, forming flanges at thoselocations with fixing holes in those flanges outside the seal of thedouble glazing unit for the attachment of clamps for securing the doubleglazing unit to a supporting member.
 5. A glass roof structure includinga number of structural glass units which are inclined and are positionededge-to-edge, each said structural glass unit comprising a glassassembly including at least two parallel glass sheets assembledtogether, the glass assembly being inclined at an angle of at least 15°to the vertical and supported principally at opposite upper and lowerhorizontal margins and having a stepped configuration at locations onsaid lower margin where the glass assembly is secured to a supportingmember of the roof structure by clamps which are clamped to one glasssheet only of the glass assembly so that said lower margin is not freeto flex and the glass assembly is subject to a bending moment about saidlower margin, said at least two glass sheets being connected to oneanother independently of said supporting member.
 6. A glass roofstructure as claimed in claim 5, wherein said lower margin of theclamped glass sheet of each glass assembly overlies a gutter of theroof.
 7. A glass roof structure comprising two series of glassassemblies co-operating to form a ridge roof with the glass assembliesof each series positioned edge-to-edge, each glass assembly including atleast two parallel glass sheets and having lower and upper margins, eachglass assembly having a stepped configuration at its lower margin whichis secured to a supporting member of the roof structure by at least oneclamp which is clamped to one glass sheet only of the glass assembly,and knuckle joints which interconnect the upper margins of said twoseries of glass assemblies just below a roof apex, the knuckle jointshaving components which are secured to said two series of glassassemblies, each knuckle joint including two mutually interlocking partswhich are adapted to permit flexing of the glass assemblies of eachseries under changing wind loads on the glass assemblies.
 8. A glassroof structure as claimed in claim 7, wherein abutting edges of theglass assemblies of each series are spanned near their upper margins bythe knuckle joints.
 9. A glass roof structure comprising two series ofsealed double glazing units co-operating to form a ridge roof, with thedouble glazing units of each series positioned edge-to-edge, each doubleglazing unit including an inner pane and an outer pane and having upperand lower margins and wherein the inner pane of each double glazing unitis inset from its outer pane to form a stepped configuration, said lowermargin of the outer pane of each double glazing unit being clamped to asupporting member for the roof outside the seal of the double glazingunit, and knuckle joints which interconnect the upper margins of the twoseries of double glazing units just below a roof apex, the knucklejoints having components which are secured to said two series of doubleglazing units by fixing assemblies attached to the outer panes of thedouble glazing units without impairing the seals of those units, eachknuckle joint including two mutually interlocking parts which areadapted to permit flexing of the sealed double glazing units of eachseries under changing wind loads on the sealed double glazing units. 10.A glass roof structure as claimed in claim 9, wherein the inner pane ofeach double glazing unit is inset from the outer pane at least at twolocations along the lower margin of the double glazing unit, formingflanges at those locations with fixing holes in those flanges outsidethe seal of the double glazing unit, for the attachment of clamps forsecuring the double glazing unit to said supporting member of the roofstructure.
 11. A glass roof structure as claimed in claim 9 or claim 10,wherein each fixing assembly passes through a sealed hole in the innerpane of a double glazing unit, within a perimeter seal of the doubleglazing unit, with a clearance sufficient to facilitate the flexing ofthe double glazing unit under wind load, and that fixing assembly passesthrough a hole in the outer pane of the unit and is clamped to thatouter pane only.
 12. A glass roof structure as claimed in claim 11,wherein each fixing assembly includes a boss positioned between andsealed to both panes of the double glazing unit.
 13. A glass roofstructure as claimed in claim 9, wherein abutting edges of the doubleglazing units of each series are spanned near the upper margins by theknuckle joints.